Method for producing a fuel injector

ABSTRACT

A fuel injector, including a valve insert and a plug extrusion coating, is described, the valve insert including a valve sear and a valve housing. The valve housing has an alignment device, which is equipped to align the valve insert in an injection molding die, and the plastic extrusion coating has a second alignment device which is equipped to align the fuel injector during assembly in an internal combustion engine.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a divisional application of U.S. patentapplication Ser. No. 14/130,244, filed Mar. 24, 2014, which is aNational Phase of International Application, PCT/EP2012/058993, filedMay 15, 2012, and claims priority to German Patent Application No. 102011 078 251.6, filed Jun. 29, 2011, all of which are herebyincorporated by reference in their entireties.

FIELD OF THE INVENTION

The present invention relates to a fuel injector as well as a method forproducing such an injection valve.

BACKGROUND INFORMATION

Fuel injectors are known in different embodiments, in connection withinternal combustion engines, for injecting fuel. In this connection, foreach different internal combustion engine, a specific design has to bemade of an injection jet of the fuel injector. This further raises thecondition that the fuel injector be installed in the internal combustionengine with reference to its position. Up to now, this alignment hasalways taken place via torsional fixings which were applied on the fuelinjector, mostly on the plug, and which enable position alignment. Inthis context, however, the assembly of the fuel injector is veryeffortful, since the alignment of the valve seat to the plug insertionduring mounting takes place, for example, using a camera or indirectlyon an external alignment area as transfer of the position. It wouldtherefore be desirable to provide a fuel injector which particularlyenables simple and more rapid mounting.

SUMMARY

By contrast, the fuel injector according to the, present invention hasthe advantage that it is much simpler and quicker to install it.Compared to the related art, the production costs may be reduced for thefuel injector according to the present invention, in this context.According to the present invention, this is achieved in that the fuelinjector, at a valve insert, has a valve housing, a first device foraligning the valve insert in an injection molding die. Furthermore,according to the present invention, the plastic extrusion coating has asecond device for aligning, which is equipped to align the fuel injectorduring mounting on an internal combustion engine. Consequently,according to the present invention, depending upon the internalcombustion engine, an injection molding die may be provided, a valveinsert being situated in an aligned manner in the injection molding diebased on the first alignment device on the valve housing. Subsequently,a plastic extrusion coating is injected particularly for the plug andadditional outer plastic parts, if necessary, on the fuel injector. Inthis context, the second device is created for aligning on the plasticextrusion coating, so that, based on the previous alignment of the valveinsert in the injection molding die, a jet path of the fuel injector isaligned, relative to the second device, for aligning on the plasticextrusion coating. Consequently, a fixed relationship is producedbetween the second alignment device and the valve seat, and with that,the jet path. Thus, to be sure, just as has been done up to now, aninjection molding die has to be provided for each type of internalcombustion engine, but then the assembly of the fuel injector is clearlyable to be simplified. For the final assembly in the internal combustionengine, one then only has still to align the second alignment deviceprotruding during assembly from the cylinder head on a component of theinternal combustion engine, e.g. a rail, and mount it, in particular bywelding it. Consequently, according to the present invention, areference point is able to be created for aligning on the plasticextrusion coating at the lowest cost, which is individual depending onthe internal combustion engine, so that, for each internal combustionengine, a specific jet alignment of the fuel injector is possible,similar valve inserts nevertheless being able to be used which are onlyinserted in various positions depending on the injection molding die.

The first device for aligning is preferably situated at an end region ofthe valve insert, adjacent to a valve seat. A particularly compactsystem of the device for aligning may be obtained thereby.

In an especially preferred manner, the device for aligning on a valvehousing includes at least one first and one second area. The areas areto be produced simply as alignment devices and they make possible arapid insertion of the valve insert in the injection molding die.Alternatively or in addition, the device for aligning includesprojecting ribs or grooves and/or other projections.

In one particularly preferred manner, the first and second areas arearranged parallel to each other, in this instance. Alternatively, thetwo areas may be arranged to be at an angle, between the two areas atransitional edge being provided, in a particularly preferable manner,

Furthermore, the present invention relates to a method for producingfuel injectors, in a first step, a valve insert being provided having atleast one first device for aligning the valve insert. Subsequently, thevalve insert is introduced into an injection molding die, the valveinsert being aligned in the injection molding die using the firstalignment device. Then a partial molding of the valve insert usingplastic takes place in such a way that the plastic extrusion coating hasa second device for aligning. In the case of assembly of the fuelinjector according to the present invention, the latter is then alignedat the second alignment for aligning, which is provided on the plasticextrusion coating. Consequently, during the plastic extrusion coating, arelationship is produced between the first alignment unit at the valveinsert and the molded second alignment unit on the plastic extrusioncoating, whereby the jet path of the fuel injector is defined by theinsertion direction specified by the second alignment device.

In this context, the present invention may be used both forself-ignition and externally supplied ignition internal combustionengines.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 a schematic side view of a aid injector according to a preferredembodiment of the present in

FIG. 2 shows a schematic view from in front of the fuel injector of FIG.1.

DETAILED DESCRIPTION

FIG. 1 shows schematically a fuel injector according to a preferredexemplary embodiment of the present invention. Fuel injector l includesa valve insert 2, which is able to be developed as a magnetic valve or apiezo valve, in a known manner. At one end of valve insert 2, a valveseat 3 is provided, on which an injection of fuel is carried out.

Fuel injector 1, according to the present invention, includes a plasticextrusion coating 7, which in this exemplary embodiment is a plugcoating.

As may particularly also be seen in FIG. 2, valve insert 2 has a valvehousing 4, at whose outer side an alignment device 5 is providedadjacent to valve seat 3. Alignment device 5 includes a first area 6 aand a second area 6 b. The two areas 6 a, 6 b are situated at apredetermined angle ALPHA to each other and have a transitional edge 9between them Moreover, at plastic extrusion coating 7, a secondalignment device 8 is developed in the form of an additional area.

Now, according to the present invention, in the production of fuelinjector 1, valve insert 2 is able to be inserted into an extrusion formusing first alignment device 5, and the two areas 6 a, 6 b of alignmentdevice 5 ensure that valve insert 2 is inserted in a predeterminedalignment in the die mold. In a next step, plastic extrusion coating 7is then sprayed onto valve insert 2, second alignment device 8 beingsprayed on in the form of the area corresponding to the shape of thearea. Consequently, it may be ensured by the molding process that thesecond alignment device 8 is aligned relative to valve insert 2.

Thus, according to the present invention, plastic extrusion coating 7 isable to be sprayed in the correct position on valve insert 2, so that inthe subsequent insertion of the fuel injector into the internalcombustion engine only an alignment to second alignment device 8 ofplastic extrusion coating 7 is required. According to the presentinvention, one is particularly able to avoid a costly and long-drawn outalignment using a camera during assembly of the fuel injector. And yet,according to the present invention, no additional component is required,only, for each type of internal combustion engine, various die moldshave to be kept in reserve, to make possible the appropriate alignmentof the valve insert for the spraying process. Furthermore, according tothe present invention, for various fuel injectors of differentmanufacturers, in each case the same valve inserts 2 may be used, whichin each case are aligned individually in the various extrusion moldsusing first alignment device 5.

1. A fuel injector, comprising: a valve insert; and a plug extrusioncoating, wherein: the valve insert includes a valve seat and a valvehousing, the valve housing includes a first alignment device equipped toalign the valve insert in an injection molding die, and the plasticextrusion coating includes a second alignment device equipped to alignthe fuel injector while the fuel injector is being assembled in aninternal combustion engine,
 2. The fuel injector as recited in claim 1,wherein the first alignment device is situated at an end region of thevalve insert adjacent to the valve seat.
 3. The fuel injector as recitedin claim wherein the first alignment device includes at least one firstarea and one second area.
 4. The fuel injector as recited in claim 3,wherein the first area is situated in parallel to the second area. 5.The fuel injector as recited in claim 3, wherein the fast area issituated at an angle to the second area.
 6. The fuel injector as recitedin claim 5, wherein the first area and the second area have a transitionedge between them.
 7. The fuel injector as recited in claim 1, whereinthe second alignment device includes an area.